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Su T, Liu P, Ti X, Wu S, Xue X, Wang Z, Dioum E, Zhang Q. ΗΙF1α, EGR1 and SP1 co-regulate the erythropoietin receptor expression under hypoxia: an essential role in the growth of non-small cell lung cancer cells. Cell Commun Signal 2019; 17:152. [PMID: 31752873 PMCID: PMC6869211 DOI: 10.1186/s12964-019-0458-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/10/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Overexpression of erythropoietin (EPO) and EPO receptor (EPO-R) is associated with poor prognosis in non-small-cell lung carcinoma (NSCLC). Hypoxia, a potent EPO inducer, is a major stimulating factor in the growth of solid tumors. However, how EPO-R expression is regulated under hypoxia is largely unknown. METHODS The role of EPO-R in NSCLC cell proliferation was assessed by RNA interference in vitro. Luciferase reporter assays were performed to map the promoter elements involved in the EPO-R mRNA transcription. Nuclear co-immunoprecipitation and chromatin immunoprecipitation were performed to assess the interaction among transcription factors HIF1α, SP1, and EGR1 in the regulation of EPO-R under hypoxia. The expression of key EPO-R transcription factors in clinical specimens were determined by immunohistochemistry. RESULTS Hypoxia induced a dosage and time dependent EPO-R mRNA expression in NSCLC cells. Knockdown of EPO-R reduced NSCLC cell growth under hypoxia (P < 0.05). Mechanistically, a SP1-EGR1 overlapped DNA binding sequence was essential to the hypoxia induced EPO-R transcription. In the early phase of hypoxia, HIF1α interacted with EGR1 that negatively regulated EPO-R. With the exit of EGR1 in late phase, HIF1α positively regulated EPO-R expression through additive interaction with SP1. In clinical NSCLC specimen, SP1 was positively while EGR1 was negatively associated with active EPO-R expression (P < 0.05). CONCLUSIONS HIF1α, SP1 and EGR1 mediated EPO-R expression played an essential role in hypoxia-induced NSCLC cell proliferation. Our study presents a novel mechanism of EPO-R regulation in the tumor cells, which may provide information support for NSCLC diagnosis and treatment.
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Affiliation(s)
- Tianhong Su
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, 2 Hoblitzelle, Suite 252, 3500 Gaston Avenue, Dallas, TX, 75246, USA
- Department of Liver Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong, China
| | - Pi Liu
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, 2 Hoblitzelle, Suite 252, 3500 Gaston Avenue, Dallas, TX, 75246, USA
- Department of Gastroenterology, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Xinyu Ti
- Department of Respiratory Medicine, the Fourth Military Medical University, Xi'an, 710032, China
| | - Shouzhen Wu
- Shaanxi Institute of Pediatric Diseases, Xi'an Children's Hospital, Xi'an, 710003, China
| | - Xiaochang Xue
- State Key Laboratory of Cancer Biology, Biotechnology Center, School of Pharmacy, The Fourth Military Medical University, Xi'an, 710032, China
- Present Address: Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwestern China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Zenglu Wang
- State Key Laboratory of Cancer Biology, Biotechnology Center, School of Pharmacy, The Fourth Military Medical University, Xi'an, 710032, China
| | - Elhardji Dioum
- Department of Pharmacology, Department of Internal Medicine, the University of Texas Southwestern Medical School, Dallas, TX, 75390, USA
- Present Address: Diabetes Department, Nestle Institute of Health Science, EPFL Campus, 1015, Lausanne, Switzerland
| | - Qiuyang Zhang
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, 2 Hoblitzelle, Suite 252, 3500 Gaston Avenue, Dallas, TX, 75246, USA.
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